UNIVERSITY OF AGRICULTURE, ABEOKUTA OGUN STATE ...

UNIVERSITY OF AGRICULTURE, ABEOKUTA
OGUN STATE, NIGERIA
IN PARTIAL FULFILLMENT OF THE REQillREMENT FOR THE AWARD OF THE
DEGREE OF BACHELOR IN AGRICULTURE

support I have consistently enjoyed from my parents, Mr and Mrs. B. O. Uthman. They are
t
loving parents and it is my prayer that God shall make them enjoy the fiuits of their labor and

This project is dedicated to all farmers who are conscious of sustainable land use thereby preserving
the natural resource for the benefit of generations yet unborn.

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TABLE OF CONTENT
Page
Title page 1
Certification 2
Acknowledgement 3
Dedication 4
Table of Content 5
List of Tables 6
M&~t 7
Chapter One: Introduction 8
Chapter Two: Literature review 10
2.1. Fallow management and soil productivity 10
2.2. Crop-live&ockproduction systems in Nigeria 11
2.3. Tillage practices in Nigeria 11
2.4. Soil Management in relation to upland rice production 12
Chapter 3: Materials and methods 14
3.1. Study area 14
3.2. Field experiment 14
3.3. Soil samplingand analysis 15
3.4. Poultry manure 16
3.5. Crop growth and yieldparameters 17
3.6. Data analysis 17
Chapter 4: Results and discussion 18
4.1 Soil particle size distribution and bulk density 18
4.2 Soil chemical properties and nutrient concentration of poultry manure 20
4.3. Growth of upland rice 22
4.4. Rice yield 24
Chapter 5: Conclusion 25
References 26

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LIST OF TABLES
Table Title Page
I
Surface soil particle size distribution and bulk density
before planting rice in February 2001 in southwestern
Nigeria 19
2 Surface chemical characteristics of unburned and
burned locations at the experimental site in 200 I in
southwestern Nigeria 21
3 Effect of tillage on upland rice height, ground cover
and shoot: root ratio in 2001 in southwestern
Nigeria
4 Effect of poultry manure application on upland rice
23
height, ground cover and shoot: root ratio in 2001 in
southwestern Nigeria 23
5 Growth differences between two upland rice in 200 I
in southwestern Nigeria
6 Paddy rice yields between two upland rice varieties
23
cultivated on a gravelly Alfisol in 200 I at Alahata,
Abeokuta, southwestern Nigeria 24

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ABSTRACT
Gravelly, coarse-textured soils are prevalent in southwestern Nigeria. These soils are
inherently low in productivity and will require inputs for sustainable crop production. The
management of the soils with low-input technologies for the enhancement of upland rice yields
will lead to poverty and hunger alleviation in Nigeria. Therefore, this study was carried out in the
main campus of the University of Agriculture, Abeokuta southwestern Nigeria in 2001 to
determine the response of two upland rice varieties (ITA 150 and WAB 189-B-B-B-8-HB) to
hoe tillage and poultry manure application at a rate of 15 t/ha. There were three replications
in
the randomized
complete block field experiment. The effects of tillage on rice growth and yield
was obscured by the dominance of sand and gravel in particle size distribution. Although, poultry
manure application had no significant effect on rice growth and yield, it resulted in a paddy rice
yield of 1.7 t/ha which was comparable to expected
yield of rice in Nigeria or under intensive
cultivation. Upland rice cultivation at the site required cover cropping or mulching because
ground coverage by rice at 7 weeks after planting was less than 20%. Significant yield
differences were found between the two rice varieties. The variety, WAB-189-B-B-B-8-HB
yielded 1.3 t/ha while ITA 150 yielded 0.6 t/ha paddy rice. Thus, selection of an adaptable, highyielding
variety such as WAB-189-B-B-B-8-HB and application of poultry manure equal to or
less than 15 t/ha would enhance upland rice production
at the site.

Rice (Oryza sativa L.) is one of the major food crops in the tropics, particularly in Asia.
Its importance as a staple food crop has grown in Africa as indicated by its importation by
various countries in the continent (WARDA, 2000). In Africa, upland rice production constitutes
60% of the total rice-growing areas (Jacquot and Courtois, 1987).
Upland soils in the tropics are generally coarse-textured with low fertility (Lal, 1987;
2000). Although rice is adapted to a wide range of environmental conditions, its production on
the uplands of the tropics require proper management to enhance adequate supply of nutrient and
water. Vigorous growth of any crop under a highly productive soil will lead to profitable yields.
However, soil management is very important in ensuring that even a productive soil gives a
profitable yield since soil productivity is a function of soil physical, chemical and biological
fertility. For instance, a soil containing adequate nutrients may not be productive if it is
compacted.
Manual soil tillage (physical manipulation of soil) and poultry manure application
influence soil physical, chemical and biological properties. These are soil management practices
that low-income farmers growing rice in Nigeria can adopt. Although, the benefits from the
proper use of inorganic fertilizers have been demonstrated over the years, the cost of purchasing
them may be prohibitive or they may not even be easily obtained in a developing nation like
Nigeria.
The gravel concentration and dominance of sand in particle size distribution of soils in
southwestern Nigeria (Lal, 1987) and their hardsetting properties (Ley et al., 1989) indicate that
tillage and the use of organic manure can enhance soil productivity in the region. This hypothesis

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needs to be tested for upland rice varieties which farmers in the region are likely to adopt

Shifting cultivation is the traditional practice of leaving a degraded agricultural land to
fallow for a period, which in the past could be more than 10 years, so that the productivity of the
soil can be restored (Sanchez, 1976; Ruthernberg, 1980). Although, fallowing is still a practice in
tropical agriculture, the length of fallow has shortened and in some cases farmers virtually crop
their land continuously.
The concept of planted or managed fallow in which the land user intervenes in the choice
and growth of fallow species in order to accelerate soil productivity restoration has been tested in
southwestern Nigeria on degraded Alfisols (Hulugalle, 1992; Hulugalle, 1994; Kang et aI., 1997;
Salako and Tian, 2001; Salako et al., 2001). The results of the various researchers showed that
soil physical fertility was particularly not rapidly restored
of soils was also crucial for sustainable crop production.
and also that post-fallow management
Such post-fallow management practices
include cover cropping, agroforestry, conservation tillage and judicious use of organic and
inorganic soil amendments.
Soil management during cultivation of arable crops is a chief determinant of the
sustainability of agricultural practices. The soil must be productive
for a long time if farmers are
to be prevented from clearing new areas with the consequence of loosing the forest vegetation
which have taken years to grow. Thus, there is a need to maintain the soil at an optimal level of
physical, chemical and biological fertility during crop production
(Lal, 1987). Soils, particularly

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Alfisols, in southwestern Nigeria are highly vulnerable to soil erosion and this can be

12
nations, manual tillage is practiced and this is done to make raised beds or mounds

13
was a combination of minimum tillage and rice residue mulch. Since the availability of residue
and addition of 15 t 00- 1 farmyard manure can significantly improve millet grain yield in

3.1. Study Area
The study was conducted at the University of Agriculture, Abeokuta (latitude 7.13 N and
longitude 3.28 E), southwestern Nigeria. Mean annual rainfall is 1200 mm and it is bimodally
distributed. The site is a derived savanna
zone and the soil is a gravelly Alfisol.
3.2. Field Experiment
This study was part of an experiment established in January 2001. The experiment was
established as a randomized
complete block design with three replications. The site was cleared
and biomass burned in February 2001. Composite
soil samples were collected at 0-15 cm depth
after biomass burning for soil chemical analyses. Also, poultry manure was collected from a
poultry farm in the vicinity of the experimental site for the experiment.
3.2.1. Plot layout an~Treatments
Each plot size was 3 x 4 m.
Level tillage was carried out with hand hoe on designated
plots. There were also no tillage plots but these were disturbed minimally during land
preparation. Two upland rice varieties, ITA 150 and WAB 189 B-B-B-8-HB, planted on April 5
2001 were considered in this study. These treatments were considered in pairs as follows:
• Poultry manure applied in March at 15 t ha- 1 versus no poultry manure
• Level tillage (15 cm deep) versus no-tillage (except minimum disturbance)
• Rice varieties: ITA 150 and WAB 189

Composite soil samples were taken in February before plot layout, before planting. However, the
site vegetation had been burned by accidental :firethen. Therefore, another location close to the
site but unaffected by :firewas sampled. The composite surface (0- 15cm) soil samples were airdried
and passed through
a 2 mm sieve for particle size distribution and soil chemical analyses.
Also, a fraction of the soil sample was ground and passed through
0.5 mm sieve for organic
carbon determination. "Undisturbed" core samples (0- 6 em) were also taken for bulk density
determination in March after plot layout and tillage. Procedures and methods used for soil
chemical analyses are described by UTA (1979) and Anderson and Ingram (1993) whereas those
used for soil physical properties are described by Klute (1986).
Particle size distribution was determined by pipette method (Gee and Bauder, 198, Sheldrick and
Wang, 1993). Fifty grams of each soil sample was dispersed in a plastic bottle with sodium
hexamataphosdphate
overnight after the removal of organic matter by the addition of hydrogen
peroxide. It was then shaken overnight before being turned into a 1000 ml
measuring cylinder
for measurement with pipette at specified depth related to room temperature. Gravel content of
air-dried soil was measured by collecting gravel retained on 2 mm sieve and weighing it relative
to the total soil weight.

A core sample which was 7 cm deep and 10 cm in diameter was used to take "undisturbed"
core
samples (Blake and Hartge, 1986). This was difficult because of gravel concentration. Soil bulk
density was obtained by taking three core samples from a plot into a large tin. The soil was ovendried
at 10SoC and the bulk density calculated as ratio of dry mass to 3 x volume of core sampler.
Soil pH was determined using 1:1 soil to water ratio and a pH meter. The electrode
of the pH
meter was inunersed in the supernatant. Soil organic carbon was determined using the Walkey-
Black method and total nitrogen using the Kjedahl method. Available phosphorus was
determined by Bray-l method. A flame photometer was used for the determination ofK, Ca and
Na using supernatant obtained by leaching with NILOAC. An atomic absorption spectrometer
was used for determination ofMg and Mn.
A composite sample of the poultry manure passed though O.S mm sieve was analyzed for
concentrations of N, P and K using procedures for plant analyses as described in UTA (1979)

Average plant height for 10 stands of rice was determined
at 6 weeks after planting rice in May
2001. Ground cover by rice was measured using the beaded string method (Sarrantonio, 1991) at
7 weeks after planting (WAP). The method involved marking a string at 15 cm interval and
running it across in two diagonal directions on the rice plot. The number of dots striking a leaf
was recorded for each diagonal. Number of dots striking the leaves divided by the total number
of dots for each diagonal, multiplied by 100 gave to total ground cover for the plot.
At lOW AP, single stands of rice were excavated from each plot. The dry weights of the
aboveground biomass and below ground biomass were taken. From this shoot (aboveground) :
root (belowground)
ratio was calculated for each treatment.
Rice paddy yield was determined in July, at about
16 WAP rice. An inner area of2 x 3 m
was harvested at various times in July due to variation in maturity of rice. The paddy rice was
removed
from the panicles after drying to a constant weight and the yield (weight) per hectare
was calculated.
Soil particle size distribution and chemical properties were described statistically by calculating
means, standard error and ranges. However, analysis of variance (Hinkelmann and Kempthome,
1994) was carried out for crop growth parameters to compare .tillage treatments, poultry manure
treatments
and rice varieties. The least significant difference at 5% probability level was used for
the comparison.

Surface soil at the site was sandy loam at the surface (Table la). Gravel concentration
in
air-dried soil was 466 glkg (± 32 standard error, n = 13 samples). The ranges of values observed
for silt and clay were wide and clay content was low. Low amount of clay and high amount of
sand suggest that the soil would be poor in chemical fertility because exchange of ions in soil is a
function of both the amount and type of clay (Brady and Weil, 1999).
The range of soil bulk density was also wide (Table Ib). This could be attributed to the
small depth of sampling (0-7 cm). The minimum values were observed where surface litter still
existed whereas the maximum values were observed where substantial gravel was sampled with
soil. This could be seen by the observation that the numerical minimum value for the level tillage
was greater than the minimum bulk density in the no tillage plot.
In sampling the gravelly soil
for soil bulk density, there was a tendency to select only spots where core samplers could be
knocked into the soil. This constitutes a bias. Nonetheless, representative samples were taken in
this study as indicated by the range. Management
of the soil at this site for high productivity
would require that the litter layer be protected during cultivation as it complements the low
activity clay in supply of nutrients and structural stability (Salako and Tian, 2001; Salako 2001).

Table 1. Surface soil particle size distribution (g/kg) and bulk density (g/cm 3 )
before planting
rice in February 2001 in southwestern Nigeria
a. Soil particle size distribution (4 composite samples)
Sand Silt Clay
Mean 828 134 38
Minimum 718 93 17
Maximum 872 228 53
Standard error 12.64 40 3
Mean
Minimum
Maximum
Standard error
No-tillage
1.30
0.68
1.76
0.10
Level tillage
1.38
0.81
1.76
0.09

Soil pH increased by 9% due to burning at the site (Tables 2a and 2b). However, the
highest increase due to burning of fallow vegetation was observed with regard to extractable P
while there was no change in exchangeable Mn content. Total nitrogen decreased. The unburned
site (Table 2a) showed that the soil was inherently acidic and low in fertility. Soil organic carbon
is low. The decrease of total nitrogen can be attributed to volatilization which could occur due to
increase in soil pH caused by burning or by direct effect of burning (Brady and Weil, 1999).
Burning of cleared vegetation is a common practice among farmers in the tropics. This practice
leads to
immediate improvement of soil fertility but it is not often sustainable as the
improvement observed is lost after one year of cultivation (Kang et aI., 1997, Salako and Tian,
2001).
Concentration ofN in the poultry manure was 27 g /kg, P was 113 glkg and K was 35
g/kg. For wetland rice production in Punjab, India, Singh et aI. (1987) reported that poultry
manure that contained 18.5 glkg N and 18.1 glkg P was 80% efficient as urea N in terms of N
uptake. Efficient use of N by crop in coarse-textured soil is important, as considerable N
leaching can occur even with application of poultry manure (Sim , 1987). According to Sim
(1987), tillage can encourage the utilization of N from poultry manure. Therefore, it is expected
that nutrient stock at this study site would be improved by biomass burning and poultry manure
application in spite of the coarse texture of the soil.

Table 2: Surface (0-15 cm) chemical characteristics
of unburned and burned
locations at the experimental site in 2001 in southwestern
Nigeria
Descriptive
pH
OrgC.
Total
Brayl P
statistics
(I: I
(glkg)
N
(mglkg)
H20)
(glkg)
Descriptive
pH
OrgC.
Total N
Brayl P
statistics
(1: I
(glkg)
(glkg)
(mglkg)
H20)

Growth of upland rice was not significantly affected by tillage (Table 3). Soil coverage
by rice was poor at 7 WAP and shoot growth was 3 times higher that root growth at 10 WAP.
Lack of significance between no tillage and level tillage was attributed to the fact to soil effect of
the dominance of sand and presence of gravel in particle size distribution (Table 1), which would
cause poor aggregation and low structural stability (Salako et aI., 1999; Salako, 2001). As
indicated in Tablelb, soil bulk density at the surface did not appear too different for the two
tillage practices. Furthermore, the no-tillage treatment could be described as minimum tillage
due to disturbances which made at least the 0-5 cm depth at the site vulnerable to physical
manipulation during land preparation and planting. The vulnerability of the structure of this soil
also implies that additional cover by mulching or cover crop was necessary
with upland rice
cultivation because only about 15% of the soil was protected by rice leaves (Table 3).
Also, application of 15 t ha- l poultry manure did not have any significant effect on rice
growth parameters (Table 4). It was observed, however, that shoot growth of rice was about 1.8
times greater for poultry application than shoot growth for none application whereas it was
almost the same for tillage effects (Tables 3 and 4). This suggests that poultry manure
contributed to shoot growth of rice more than tillage. Nutrients such as N often result in high
shoot: root ratio among other factors such as age of plant and soil physical conditions
(Russell,
1977).
The two upland rice varieties (WAB 189 and ITA 150) had similar growth characteristics
under the tillage and manure application practices
(Table 5). The small difference between the
shoot: root ratios of the two varieties support the deduction that they it was poultry manure
application which boosted shoot growth at the site.

2001 in southwestern Nigeria
Soil amendment
Plant height (em) Ground Cover (%) Shoot: Root ratio
6WAP 7WAP 10 WAP
Poultry 27.9 13 4.4
None 26.9 II 2.4
LSD(0.05) NS NS NS
Nigeria
Upland rice variety
Plant height (em) Ground Cover (%) Shoot: Root ratio
6WAP 7WAP 10 WAP
WABl89 34.5 17 5.3
ITAl50 28.9 15 4.4
LSD (0.05) NS NS NS

Poultry manure application resulted in paddy rice yield of 1.7 t/ha which was not
significantly different from the yield of 0.7 tlha observed for non-application. Significant yield
differences were, however observed, between the rice varieties (Table 6). Jacquot and Courtois
(1987) observed that upland rice yield less than 1 t/ha is often obtained where traditional
methods are used but yield can be as high as 2.5 t/ha in intensively cultivated area but high
variations in yields should be expected for upland rice due to vagaries of climate. Average yield
of paddy rice in Nigeria is 1.7 tIha (WARDA, 2000). From these reports, it is concluded that rice
yields at the present study site could be enhanced by application of 15 tIha poultry manure and
the cultivation of the rice variety, WAB 189-B-B-B-8-HB
Table 6: Paddy rice yield of two upland rice varieties cultivated on a gravelly Alfisol in 2001 at
Nabata,
Abeokuta, southwestern Nigeria
Rice variety
WAB189
ITA150
LSD (0.05)
Paddy rice (tlha)
1.28
0.57
0.475

In this study, the effects of tillage, poultry manure and variety on upland rice growth and
yield were investigated in Abeokuta, southwestern Nigeria. Due to the dominance of sand and
high concentration of gravel in surface soil, there was no response of rice to tillage. Although,
significant differences were not observed for growth parameters and paddy rice yields between 0
and 15 t/ha application rates of poultry manure, the study demonstrated that rice growth and
yield could be boosted with manure application. Paddy rice yield of 1.7 t/ha observed for poultry
manure application is the average expected for upland rice yield in Nigeria. The variety, WAB
I89-B-B-B-8-HB
performed significantly better in terms of paddy rice yield of 1.2 t/ha
compared to 0.6 t/ha for ITA 150. Upland rice production at the site would require nutrient
supply, residue mulchingor cover cropping and selection ofa high yieldingvariety.

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